At present, most of the conventional oil (gas) refueling equipments are buried (underground) oil (gas) refueling station. In such refueling station, in order to guarantee the safety of oil (gas) refueling station, the oil (gas) storage tanks are embedded underground, so that such oil (gas) refueling station is distinguished as buried oil (gas) refueling station. In addition, some storage tanks are set above ground and form removable (also referred to as skid mounted type) above-ground refueling equipments. According to the working pressure conditions of the oil (gas) storage tank bodies, the storage tanks in the oil (gas) refueling equipments may be classified as atmospheric storage tanks and pressure-bearing tanks. According to the specification requirements for storage tank, the storage tanks in the oil (gas) refueling equipments may also be classified as standard tanks and non-standard tanks. To ensure the safety of the oil (gas) refueling equipment, the most conventional explosion prevention measure available is to fill the tank body with explosion-proof material so as to prevent the medium stored in the tank body of the oil (gas) refueling equipment, such as inflammable and or explosive dangerous chemicals in liquid or gaseous state, from combustion or explosion triggered by unexpected accidents such as static electricity, naked flame and gunshot.
The available explosion-proof material is a kind of reticular lamellar material, which is rolled into a cylinder body and is then installed into the tank body one by one as filling material. This explosion-proof material has been disclosed in the invention patent ZL 92102437. Such material is installed into the tank body as explosion proof filling material after being rolled into cylinder body. Due to long-term immersion, the material located at the lower part of tank body bears very large load, and the mutual stacking, pressing and extruding between the material bodies result in the distortion and collapse of the material, generating serious effects on the blocking and explosion-resisting abilities of such material. As a result, an explosive space will be formed in the upper part of the tank body, which tends to cause combustion and explosion. Meanwhile, because most of the available explosion-proof materials are made of metal materials, they are liable to generate scraps due to the uneven force imposed on them upon occurrence of flow surge of the medium in the storage tank body, thus bringing about disadvantageous effects on the properties of the content in the storage tank.
In addition, in case of small volume storage tanks, due to the volume restriction, the available explosion-proof materials installed as filling material in the small-volume storage tanks are generally built up in spherical structure, and are packed in great density and take up considerable occupation.
Although in short run, it is practical to avoid the “boiling liquid expanding-vapor explosion” accident of a LPG tank when the LPG tank is filled with such a explosion-proof material, such explosion-proof material is still liable to collapse after long-term use so that the explosion prevention effect cannot be achieved for the same reasons.
Practice has proved that, all kinds of oil (gas) refueling equipments filled with the conventional explosion-proof materials have shown inadequacy in terms of meeting the explosion prevention and environment protection requirements for them.